* {
  margin: 0;
  padding: 0;
  list-style: none;
  text-decoration: none;
  color: #939393;
  outline: none;
  box-sizing: border-box;
}
/* 用于清除浮动和外边距合并问题 */
.clearfix::after,
.clearfix::before {
  content: "";
  display: table;
  clear: both;
}
